Field of the Invention
The present invention relates to a water muffler incorporated into a personal watercraft.
Description of Related Art
In a personal watercraft, a water muffler is used as an exhaust gas silencer (see U.S. Pat. No. 7,326,093 B2). The water muffler includes an inlet pipe connected to an exhaust pipe extending from an engine. This inlet pipe has a double-walled structure including a center pipe wall, and an outer pipe wall formed to surround the center pipe wall. The inlet pipe is provided with an exhaust passage formed inside the center pipe wall, and a water passage surrounded by the center pipe wall and the outer pipe wall. The downstream end of the inlet pipe is formed with an outlet of the exhaust passage and an outlet of the water passage. The exhaust gas and cooling water flow into the interior of the water muffler through the outlet of the exhaust passage and the outlet of the water passage.
Typically, an exhaust gas outlet and a water outlet are placed to be coplanar with each other. For this reason, the cooling water is highly likely to flow into the exhaust passage through the exhaust gas outlet located inward relative to and close to the water outlet. As a result, the cooling water may flow back toward the engine through the exhaust passage.